Various cardiovascular procedures, such as angioplasty, stent placement and atherectomy, require inserting into and manipulating within the vasculature, wires and catheters adapted to perform those procedures. Access to the vasculature typically is through the femoral artery and is percutaneous, involving insertion of a needle in the region of the groin to form a track through subcutaneous tissue and to puncture and create an arteriotomy in the femoral artery. A short guidewire is then advanced through the needle and into the femoral artery. The needle then is removed. An introducer sheath is then advanced over the guidewire, along the track and into the femoral artery. The introducer sheath provides access into the femoral artery, through the arteriotomy, for catheters or other instrumentalities in order to perform the selected procedure.
After the procedure has been completed, the procedural devices are removed and the arteriotomy must be closed. The size of the puncture opening in the artery corresponds to the size of the catheter or percutaneous introducer sheath used, which devices may typically range in diameter from 5 French (1.67 mm) for a diagnostic procedure to 6-10 French (2.00 mm-3.33 mm) for a therapeutic procedure. A number of techniques are known to facilitate closure and healing of the arteriotomy. One technique includes application of pressure at the puncture site for a relatively extended length of time. More particularly, compression has traditionally been applied to the puncture site for at least 30-45 minutes for the wound to close naturally after removal of the catheter. Patients are required to remain decumbent, essentially motionless and often with a heavy sandbag placed on their upper leg, for several hours to ensure that clot has formed at the arteriotomy to prevent bleeding. The recovery time from the medical procedure may be as little as half of an hour, but the recovery time from the wound can exceed 24 hours. This makes wound site management the longer critical care item. The longer the recovery time, the more expensive the procedure becomes, the greater the patient discomfort, and the greater the risk of complications.
Also among the techniques for closing the arteriotomy is the use of a staple system such as described in U.S. Pat. Nos. 6,506,210, 6,767,356 and 7,074,232 to Kanner et al., the disclosures of which are incorporated by reference herein in their entirety. The Kanner patents describe a system by which the original introducer sheath is removed, leaving the guidewire in place. An assembly that includes a closure sheath and dilator is then advanced along the indwelling guidewire to bring the distal end of the sheath into proximity to the arteriotomy. The closure sheath also carries, at its distal end, an arrangement of wire-like stabilizers that, together with the dilator, pass through the arteriotomy into the artery. The system enables the portions of the stabilizer wires disposed within the artery to be formed into a temporarily enlarged shape that prevents removal of the wires through the arteriotomy and holds the sheath in place. The stabilizers and distal end of the sheath are drawn together to grip the tissue about the arteriotomy and thereby secure and fix the position of the distal end of the sheath over and in alignment with the arteriotomy. The dilator and guidewire then can be removed through the sheath, leaving the closure sheath in place adjacent the outer surface of the artery with the stabilizers within the artery, in place in readiness to provide direct access to the arteriotomy through the sheath.
A catheter-like stapling device, with a staple carried in its distal end, then is advanced through the closure sheath to locate the staple in proximity to the arteriotomy. As described more fully in the Kanner patents, the stapler and sheath include mechanisms by which the staple, when advanced through the sheath, will be oriented in registry with and at a fixed distance from the arteriotomy. When the stapler is actuated, the prongs of the staple first expand and advance toward and into the arterial wall on opposite sides of the arteriotomy. Continued operation of the stapling mechanism draws the prongs of the staple together to draw the edges of the arteriotomy together into approximation and then releases the staple. The stabilizers return to a low profile shape enabling their withdrawal from the artery. With the staple deployed and having closed the arteriotomy the stapling mechanism and sheath may be removed, leaving the staple in place. The invention herein provides a staple and stapling system that are simpler and less expensive to manufacture than previously known staples and stapling systems.